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i2c: atr: Fix end of loop test in i2c_atr_find_mapping_by_addr()

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When the list_for_each_entry_reverse() exits without hitting a break
then the list cursor points to invalid memory.  So this check for
if (c2a->fixed) is checking bogus memory.  Fix it by using a "found"
variable to track if we found what we were looking for or not.

The list head (i2c_atr_chan.alias_pairs) is not a full entry, it's just
a struct list_head. When the for loop runs to completion, c2a doesn't
point to a struct i2c_atr_alias_pair, so you can't access c2a->fixed.

Fixes: c3f5524188 ("i2c: Support dynamic address translation")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Reviewed-by: Romain Gantois <romain.gantois@bootlin.com>
Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
This commit is contained in:
Dan Carpenter 2025-04-23 11:21:18 +03:00 committed by Wolfram Sang
parent 04668774f6
commit 20d5620e9b
1 changed files with 7 additions and 3 deletions
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10
drivers/i2c/i2c-atr.c
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@ -240,6 +240,7 @@ i2c_atr_find_mapping_by_addr(struct i2c_atr_chan *chan, u16 addr)
struct i2c_atr *atr = chan->atr;
struct i2c_atr_alias_pair *c2a;
struct list_head *alias_pairs;
bool found = false;
u16 alias;
int ret;
@ -258,11 +259,14 @@ i2c_atr_find_mapping_by_addr(struct i2c_atr_chan *chan, u16 addr)
if (unlikely(list_empty(alias_pairs)))
return NULL;
list_for_each_entry_reverse(c2a, alias_pairs, node)
if (!c2a->fixed)
list_for_each_entry_reverse(c2a, alias_pairs, node) {
if (!c2a->fixed) {
found = true;
break;
}
}
if (c2a->fixed)
if (!found)
return NULL;
atr->ops->detach_addr(atr, chan->chan_id, c2a->addr);